Pressure-sensitive adhesive compositions are widely used as the coating for adhesive tapes, labels, wall coverings, bumper stickers, etc. Typical compositions are prepared by blending tackifying resins with a variety of available elastomeric materials. Recent art describes pressure-sensitive adhesives based on elastomeric block copolymers of styrene and butadiene or isoprene. For example, U.S. Pat. No. 3,932,328 to Korpman discloses a pressure-sensitive adhesive composition of an A-B-A block copolymer and a tackifier component, where A is polystyrene and B is isoprene. U.S. Pat. No. 3,954,692 to Downey discloses a pressure-sensitive adhesive composition of polystyrene - polyisoprene - polystyrene block copolymer with a special tackifier resin chosen from a variety of resins including copolymers formed from 1,3-butadiene and aliphatic monoolefins. U.S. Pat. No. 3,519,585 to Miller discloses a pressure-sensitive adhesive mixture of two styrene-butadiene block copolymers with a tackifier resin. The block copolymer may contain cis -1,4 polybutadiene. Other examples of pressure-sensitive adhesive compositions can be found in U.S. Pat. Nos. 3,427,269; 3,917,607; 3,956,223; and 4,048,124.
The above described compositions are well established as useful pressure-sensitive adhesives. However, the physical properties of these block copolymer compositions preclude their use as viable cold temperature adhesives (specifically, an adhesive for tapes or labels which is aggressively tacky and cohesively strong at ambient temperatures as well as -10.degree. F. or lower). With the present practices in the food business a pressure-sensitive adhesive tape or label which can be attached to a container (especially corrugated box board) at either cold temperature or ambient temperature is highly desirable. Block copolymer resin formulations can be sufficiently softened by plasticizer additions so as to be tacky at -10.degree. F., but such compositions will then lack sufficient cohesive strength at ambient temperatures and cause difficulties in the preparation and storage of the tapes or labels.